Rangers boss Walter Smith praised Hearts' title push after defeat yesterday.
Ryan Stevenson grabbed the only goal of the game for the Jambos against Rangers at Tynecastle as they moved to within two points of the Scottish champions.
Smith said: "It's a welcome enough challenge.
"Hearts, when they are on form as they are at the moment, are always going to be challengers. I don't see anything in their play that would suggest they will get any weaker as the season goes on.
"It's a welcome challenge but frustrating today considering the way we played. We are just a bit unhappy about the fact that we haven't managed to do better in terms of getting the result."